Marinate Chicken: In a mixing bowl, whisk together harissa paste, honey, olive oil, lemon juice, minced garlic, cumin, smoked paprika, salt, and black pepper. Add diced chicken thighs and toss thoroughly to coat every piece. Let marinate for at least 15 minutes at room temperature (or up to 8 hours refrigerated).
Whip the Feta: Place crumbled feta cheese, Greek yogurt, olive oil, lemon juice, and grated garlic into a food processor or high-speed blender. Blend on high speed for 60 to 90 seconds, scraping down the sides as needed, until the texture becomes silky smooth and cloud-like. Taste and adjust lemon juice if desired.
Sear Chicken: Heat a large cast-iron skillet or grill pan over medium-high heat with 1 tablespoon of olive oil. Once shimmering hot, add chicken in a single layer without overcrowding. Sear undisturbed for 4 to 5 minutes until deep golden-brown caramelized grill marks form. Flip and cook for another 3 to 4 minutes until juices run clear and internal temp reaches 165°F (74°C). Brush remaining pan glaze over the chicken and remove from heat.
Assemble Grain Bowls: Divide warm seasoned pearl couscous evenly into 4 wide shallow bowls. Top each bowl with sliced charred honey harissa chicken, a generous swoop of velvety whipped feta, diced cucumbers, quick-pickled red onions, and Kalamata olives.
Garnish & Serve: Drizzle each bowl with extra virgin olive oil, sprinkle with fresh mint leaves and parsley, and serve immediately with warm fluffy pita bread on the side.